As the title says, below are some pics on real hardware and clone ones: Hyperkin Supaboy SFC, SuperNT.
As you notice, the gray frame is closed to the logo.



This one is real hardware on CRT TV. The result is the same.

However, when I run on emulators like Snes9X and even BSNES, the one said to be the most accuracy emulator, the gray frame is not CLOSED to the logo as in real SFC/clone machines.

Can anyone explain why this happen? And how to cure this? I code the game to run on real machine, but I use emulators to quick test, so it's important to adjust the emulators close to real machine.
Note: this doesn't matter with the screen setting on emulators. I tried every setting and nothing change.